1. Technical Field
This invention relates in general to computers, and, more particularly, to computer networking.
2. Description of the Related Art
Since the proliferation of the personal computer as a personal and business tool, portable computers have been in high demand. Portable computer manufacturers are continually refining the portable computers to have a greater number of features while reducing the size and weight of the units. Current day portable computers have processing power equivalent to typical desktop machines.
Very low weight portable computers are referred to as "notebook" computers. At one time, notebook computers were stripped of many features in order to reduce weight and size; however, current day notebook computers are full-featured. Weight and size are among the most important factors in selecting a notebook computer. Since a notebook computer is meant to be used in many different locations, the ease with which it can be carried is often determinative of its value. Accordingly, notebook computers differ from desktop computers with respect to the keyboard size and the monitor size.
In order to provide full features to a notebook computer while the computer is in the office environment, most notebook manufacturers provide optional docking stations or port replicators, which allow the user to connect the notebook computer to a full size monitor and keyboard by slipping the notebook into an external unit on the user's desk. If the office is networked, the docking station or port replicator may also include a network connection.
FIGS. 1a and 1b illustrate a typical connection between a network interface card and a network. A network interface circuit 10 is coupled to a isolation transformer 12. The isolation transformer 12 is coupled to a connector 14, typically, a RJ45 connector, although other connectors could be used as well. A cable 16 is coupled between the connector 14 and the network 18.
FIG. 1b illustrates a schematic diagram of the isolation transformer 12. The network interface side of the isolation transformer 12 has two windings, a transmit primary winding 20 and a receive primary winding 22. The connector side of the isolation transformer 12 also has two windings, a transmit secondary winding 24 and a receive secondary winding 26. For an RJ45 connector, the transmit secondary winding 24 is coupled to pins "1" and "2" of the connector and the receive secondary winding 26 is coupled to pins "3" and "6" of the connector.
The isolation transformer 12 isolates the network circuitry 10 from DC voltages which could corrupt the network signals. These voltage would include signals from noisy electrical system grounds, ground loops, power line spikes and other power line disruptions.
However, isolation transformers do not contemplate multiple connectors being coupled to the network circuitry. Because both the portable computer and the docking station may have separate connectors which may be used to connect to the network, this presents a significant problem.
Therefore, a need has arisen for a method an apparatus for connecting multiple network connectors in a computer system to a single network interface circuit.